1. Field of the Invention
The invention relates to third rail collection devices for electric rolling stock and consists particularly in an automatic release, automatic reset impact protection device for supporting third rail engaging equipment from railway trucks and protecting the equipment from excessive vertical impacts and automatically restoring the equipment to operative position.
2. The Prior Art
In the prior art, third rail engaging equipment has commonly been mounted on unsprung parts of the vehicle trucks such as equalizer beams or journal boxes and has included a shoe operable either by gravity, or springs, to bias the shoe into electro-conductive engagement with the electrical conductor rail, usually a third rail positioned outwardly of the running rails and normally supported on crosstie-mounted brackets at a higher level than the running rails. Such equipment sometimes includes sleet scrapers spring-biased into scraping relation with the third rail.
In other instances, the third rail engaging equipment supports have been mounted on a sprung part of the truck. In both instances, the receipt of vertical impacts by the third rail engaging equipment resulting from acceleration forces caused by differential ramping between the running rails and the third rail might cause damage to the third rail engaging equipment and its mounting on the truck, and in the second instance, the receipt of vertical impacts by the third rail engaging equipment resulting from vertical movement of the sprung truck part on its springs might cause damage to the equipment and its mounting on the sprung truck part.